FI69207B - FOERFARANDE OCH DAERVID ANVAENDBAR APPARATUR VID MEKANISKA TORKMASKINER MED KONTINUERLIG DRIFT - Google Patents

Description

69207

METHOD AND APPARATUS USED IN MECHANICAL CONTINUOUS DRYERS

This method and apparatus is used in mechanical wet driers with a rotating perforated drum and a roll inside it which compresses the material to be dried, e.g. a shell between the roll and the drum, whereby water escapes through the holes in the drum.

Finnish patent application No. 781706 describes a press in which the substance to be dried, e.g. the shell, is pressed between the roll and the drum. The wet shell is fed in from the top of the oblique drum and falls between the roll and the drum. Because the shell is wet and slimy, it partially adheres to the surface of the drum-filled drum after compression. There are scrapers on the top of the drum to remove the shell for new compression. The shell falls down on top of the roll and moves with the rotating roll over the roll, falling onto the downward side of the roll for re-compression. However, this passage over the roll does not always take place evenly, and the scrapers may detach the desiccant from the drum, e.g. a shell which falls on the shell on top of the roll and thus forms a thick "lump" which impairs the compression result.

When there is little shell, a shell surface 8 'is formed (Figure 1), and on this surface the "shell balls" rotate towards the lower end of the roll. These rotating "shell balls" have to be pressed under the roll only once or 2-3 times and degrade the overall drying result.

The purpose of the method and device according to the invention is to eliminate the disadvantages described above and to make the substance to be dried evenly pressed to dryness.

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The method according to the invention, in which, in order to dry the shell or the like, the shell is fed between a rotating drum with holes and a roll rotating inside it, is characterized by the features set forth in the characterizing part of the claim. The apparatus used in the method according to the invention is characterized by the features set forth in the characterizing part of claim 5.

The invention will be explained in more detail with the aid of the accompanying drawings.

Figure 1 schematically shows the structure of a shell press before the improvement according to the invention.

Figure 2 schematically shows a structure according to the invention.

Figure 1 shows the dryer viewed in the axial direction of the drum 1. Inside it is a roller 2. Both the drum and the roller rotate in the same direction indicated by the arrows 7.

A wet drying agent, e.g. a shell, is passed between the drum and the roll to the feed point and direction of movement indicated by the arrows 3 in Fig. 1. The shell falls down and fills the downwardly tapering space 4 between the drum and the roll. As the drum and roll rotate, the shell is subjected to hard compression under the roll at 6 and water is sprayed out at the points indicated by the arrows 5. The shell adheres, depending on its resin, more or less to the inner surface of the drum.

Gradually, in Figure 1, the space 8 on the right side of the roll is filled with a shell. Thereafter, a part of the shell 9 rises over the roll and falls to the other side into the space 4. At the same time, however, the scrapers drop the shell 11 adhering to the inner surface of the drum on the shell on top of the drum, thus forming a thick lump 12.

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After falling from point 3, the entire shell is always pressed once. But if the shell comes a little, the shell surface 8 'remains down and the shell does not rise over the roll, but "shell balls" 10 are formed which roll along the surface 8' towards the lower end of the roll and remain only 1-2-3 times compressed wet.

The invention, which eliminates both of the above disadvantages, is illustrated in Figure 2 and the following description. It has a knife acting as a scraper placed approximately at the height of the drum axis towards the starting point of the pressing point. The knife blade 21 removes the shell adhering to the surface of the drum. In order to prevent the loose shell from starting to rotate in the plane 8 'between the drum and the roll and gradually flow downwards in the direction of the drum axis and thus without squeezing out of the drum, guide plates 22 are mounted in this space. The lower tip 21 of the guide plate is on the drum side very close to the surface of the drum. On the roll side, there is a gap between the edge 24 of the baffle plate and the roll because the roll rises and falls relative to the baffle plate. The inner edge 24 of the guide plate is preferably sharp. The sharp edge 24 is able to cut a branch of wood, for example, between the roller and the guide plate. The guide plate 22 widens upwards in a wedge-like manner and the upper edge 25 is almost at the height of the upper surface of the roll.

The baffles are welded to a unitary rod formed by the scrapers 20. The structure formed by the guide plates 22 and the rod is supported on a frame structure outside the drum. There may be, for example, three or four guide plates inside the drum. The number depends, for example, on the length of the drum. Between the side walls formed by the guide plates 22, the shell rises evenly to the height of the upper surface of the roll and travels on the surface of the roll to the other side of the roll, falling evenly for compression. If the roller and the drum are in an inclined position, the shell material always moves slightly forward towards the outlet when it falls and is thus compressed several times.

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The operation of a shell press in an inclined position has been described above. The shell moves toward the lower end of the press as it falls down on the feed side of the roll.

When the drying press is provided with the knife 20 described above and the guide plates attached thereto, the drum can also be in a horizontal position. In this case, the guide plates are inclined in the feed direction, i.e. their upper end is closer to the outlet end of the drum by the desired feed than the lower tip of the guide plates.

In this method according to the invention, in which the drum is in a horizontal position, the shell falls straight down on the feed side of the roll. The feed is made by the baffles 22 by moving the upwardly rising shell by the desired feed towards the outlet end of the drum.

The knife blade 21 now removes everything that has passed under the roller. from the inner surface of the drum of the shell, so that all the shell rises between the roll and the knife in the direction determined by the guide plates 22 and then over the roll, falling down on the other side of the roll for re-compression.

It is very important that the guide plates prevent the shell from "rolling" downwards when there is less shell and the shell surface 8 'shown in Fig. 1 is formed on the upward side. The width B of this surface is reduced by moving the roll by a dimension A towards the upward side of the shell. This thus prevents the shell from "rolling" between the baffles.

The displacement of the roll by dimension A also contributes to facilitating the feeding of the shell between the roll and the drum, since the width D of the feeding point 3 increases by dimension A.

With the method according to the invention, the dry matter content of the shell is increased by 4-5%.

The invention may be modified according to the circumstances within the scope of the claims.

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Claims (7)

A method for drying a shell or the like by continuous mechanical drying machines, wherein to dry the shell or the like, the shell is fed between a perforated rotating drum (1) and a rotating roll (2) therefor for compression, thereby scrapers between the drum and the roll. to be pressed from the surface and dropped for compression so that the shell, after being wound several times around the roll (2), is compressed several times before leaving the drum, characterized in that the shell rises to the roll (2) and thus falls into a new compression. ) to the height of the surface by dividing the space between the roll (2) and the drum (1) on the inlet side of the shell by transverse guide plates (22) (e.g. into three or four parts) to prevent the shell from moving in the exit direction before rising over the roll (2). A method according to claim 1, characterized in that the knives (20) acting as scrapers are formed as a rod to which the guide plates (22) are attached. * Method according to Claim 1 or 2, characterized in that the rise of the shell is controlled in such a way that * at the same time the desired feed movement in the direction of exit of the shell is obtained. Method according to Claim 1, 2 or 3, characterized in that the rise of the shell on the upstream side of the shell over the roll (2) and re-compression is facilitated by narrowing the space (B) 69207-6 between the roll (2) and the drum (1) (22) side than the supply side (D). Apparatus for use in a method according to claim 1, 2, 3 or 4, characterized in that in the space between the drum (1) and the roll (2) on the upstream side of the shell there are transverse guide plates (22) extending approximately to the top surface of the roll. in the cross-sectional shape of the space between them and whose inner edge (23) is preferably sharp. Apparatus according to claim 5, characterized in that the guide plates (22) are attached to a unitary rod, which rod at the same time forms knives (20) acting as scrapers. Apparatus according to claim 5 or 6, characterized in that the space between the roll (2) and the drum (1) on the upstream side of the material to be compressed in the region of the guide plates (22) is tapered so that the axis of the roll (2) is slightly lateral to the center of the drum (1). , wherein the pressing point (6) is a small distance in the direction of rotation from the lowest point of the circumference of the drum. Il - 7 - 69207